Health care was the top issue for Pennsylvania's 18th congressional district voters, who seemingly elected Democrat Conor Lamb over Republican Rick Saccone in a dramatically close special election on Tuesday, Public Policy Polling found. Fifty-two percent of voters said health care was a top issue in their decision and "among voters who said health care was the most important issue for them, Lamb beat Rick Saccone 64-36, and among a broader group of voters who said it was either the most important or a very important issue, Lamb beat Saccone 62-38," PPP writes.

The heavily Republican PA-18, which President Trump won by 20 points in 2016, additionally disapproved of the GOP's efforts to roll back the Affordable Care Act by a margin of 14 points, 53 percent to 39 percent. Almost half of voters, 48 percent, believe "Republicans are now trying to undermine and sabotage [the Affordable Care Act] since they failed to repeal it," and over half, 59 percent, believe the ACA should be kept in place following certain fixes. Just 38 percent believe a full repeal is the best decision.

The Pennsylvania race is being viewed as a bellwether for the 2018 midterm elections, when Democrats are hoping to flip the House. Topher Spiro, the vice president for health policy at the liberal-leaning American Progress, reacted to PPP's poll by tweeting: "BOOM. This is it. Any vulnerable Republican who voted to repeal health care is toast."

The PPP poll reached 567 PA-18 voters on election day, March 13. The margin of error is plus or minus 4.1 percent. Read the full results here. Jeva Lange

President Trump's national approval rating is still historically low — 39.8 percent in the RealClearPolitics average and 40.2 percent at FiveThirtyEight — but "as state-by-state polling of Trump's approval rating shows, the national mood really isn't so national," Nathaniel Rakich notes at FiveThirtyEight. "Voters in different corners of the country differ in how deep their anger runs — and at whom it's directed. ... To take control of the Senate, it doesn't much matter how Democrats perform elsewhere if they can't win both Nevada and Arizona and defend red-state Democrats in places like Missouri and Indiana." According to a new poll by Axios and SurveyMonkey, that could be very difficult for Democrats to pull off.

"Five Senate Democrats would lose to a Republican candidate if the election were held today and three have approval ratings under 50 percent," Axios says. Moreover, out of the 10 states Trump won and where a Senate Democrat is up for re-election, Trump's approval rating tops 50 percent in six of them — West Virginia, North Dakota, Montana, Indiana, Missouri, and Ohio. The most vulnerable Democrats, according to the survey, are Joe Manchin (W.Va.), Jon Tester (Mont.), and Claire McCaskill (Mo.).

"With the election many months away and final Republican opponents not set, these numbers are likely to change as real GOP challengers get involved in the race," Axios says, but they "underscore how hard it will be for Democrats to pick up the two seats needed to win the majority despite Trump's troubles." SurveyMonkey and Axios conducted the online poll Feb. 12-March 5 among 17,289 registered voters in the six states above plus Florida, Michigan, Wisconsin, and Pennsylvania. Axios did not provide a margin of error. Peter Weber

In late February, though, Trump's rating looks more like his dismal December numbers, which were his lowest since taking office. Trump is also approved of by 80 percent of Republicans, which represents a new low for him.

President Barack Obama also had an approval rating below 50 percent at this point in his presidency, at 49 percent. Ronald Reagan and Jimmy Carter shared the previous record for the modern lowest approval rating at this point in their presidencies, 47 percent, which is 12 points higher than Trump's current approval rating.

USA Today and Suffolk University's Political Research Center likewise found Trump back down at his lowest job approval rating since becoming president. CNN's poll, conducted by SSRS, reached 1,016 adults on cell phones or landlines between Feb. 20 and Feb. 23. The margin of error is plus or minus 3.7 percent, and you can read more of the results here. Jeva Lange

President Trump has made a determined push for arming school teachers after the Parkland, Florida, shooting last week, but voters appear divided on the issue, a new CBS News poll reveals. Half of Americans, 50 percent, are opposed to arming teachers, while 44 percent are in favor of the plan, the poll found.

"If you had a teacher who was adept at firearms, they could very well end the attack very quickly," the president said during a listening session at the White House on Wednesday. American Federation of Teachers President Randi Weingarten blasted the idea: "Teachers don't want to be armed, we want to teach," she said.

Sixty-five percent of Americans say gun laws should be stricter, up 8 points since December due to mounting support by Republicans and independents. Forty-one percent of Republicans said they would follow Trump's lead if he called for stricter laws, as he has suggested.

Overall, 87 percent of Americans want the country to spend more money on mental health screenings, 75 percent want to strengthen background checks, 56 want to ban bump stocks, and 53 percent want a nationwide ban on the AR-15, making arming teachers the least popular of the ideas being mulled.

The poll reached 1,012 adults nationwide between Feb. 20 and 22. The margin of error is plus or minus 4 points. See the full results here. Jeva Lange

Pres. Trump endorsed letting trained teachers carry weapons when he met with state & local officials. The idea has people split along party lines according to a CBS News poll. 50% of Americans are opposed to teachers carrying guns & 44% are in favor of it https://t.co/yE0OtFxDr9pic.twitter.com/GcDK15kElz

Republicans have at last seized the advantage on a generic congressional ballot following a three-month period that saw Democrats with leads between 2 and 10 points, a new Politico/Morning Consult poll found. Among registered voters, 39 percent said they would vote for a generic Republican candidate for Congress, while 38 percent said they would vote for a Democrat and 23 percent said they are undecided.

Other polls do not yet show Republicans ahead, although RealClearPolitics' average has Democrats with an advantage of 7 points on a generic ballot, down from a high of 13 points last year.

Trust over handling the economy has also swung since December to Republicans, and the GOP also has a 9-point advantage on handling jobs, a 19-point advantage on national security, and "the Democratic advantage on health care has dwindled to just 4 percentage points, down from double digits last year," Politico writes.

Forty-seven percent of Americans approve of President Trump's job performance in the Politico/Morning Consult poll. The same percentage also disapprove. The poll surveyed 1,985 registered voters between Feb. 8-12 and has a margin of error of plus or minus 2 points. Read the full results here. Jeva Lange

President Trump and the Republican Party are feeling the love. Seventy percent of Americans said the U.S. economy is "excellent" or "good" in the most recent Quinnipiac University survey — the highest percentage to respond that way since the question was first added to the poll in 2001, and up from 66 percent on Jan. 10. The latest survey also marked the first time Americans have said Trump is more responsible for the state of the economy than former President Barack Obama, 48 percent to 41 percent.

Trump is personally seeing the boost, too: His approval rating is the highest it's been in a Quinnipiac University poll in seven months, at 40 percent, although it's still "nowhere near that magic 50 percent mark," observed Tim Malloy, the assistant director of the poll. The GOP also boasts its highest favorability rating since Trump's inauguration:

"The post State of the Union bump kicks in," said Malloy. "And an attaboy on the economy doubles the pleasure for President Donald Trump." The Quinnipiac poll reached 1,333 voters between Feb. 2-5 and has a margin of error of plus or minus 3.3 percent. Read the full results here. Jeva Lange

Democrats can thank women voters for their surging advantage on a generic ballot ahead of the hugely important 2018 midterm elections, a new Washington Post/ABC News poll has found. Although white women supported Trump by nine points in 2016 and Republicans by 14 points in the 2014 midterm, the demographic has since swung to favor Democrats over Republicans by 12 points on a generic ballot.

Overall, women voters now favor Democrats by a 26-point advantage, double Hillary Clinton's margin in 2016. Independents have also swung to favor Democrats, 50 percent to 34 percent. "The swing group has been decisive in three consecutive midterm election waves, backing Republicans by 19 points in 2010 and 12 points in 2014, but supporting Democrats by 18 points in 2006 as they retook control of the House," The Washington Post writes.

Across the board, Democrats have a 15-point advantage over Republicans on a generic ballot among likely voters. In the same Washington Post/ABC News poll in November, that margin was slightly smaller, at 11 points. Experts caution that none of this means the Democrats will necessarily take back the House, qualifying a flip as "possible" but not "likely." Even though the margin looks impressive — and Democrats are only thought to need about an eight-point advantage to gain the 24 seats to win the House — some experts say the party could nevertheless "fall five seats short even if they won all contests the Cook Political Report classifies as solidly Democratic, leaning Democratic, or toss-ups," the Post adds.

The poll reached 1,005 adults between Jan. 15-18 and has a margin of error of plus or minus 3.5 points. Read the full results here. Jeva Lange

As Americans get to know first lady Melania Trump, their opinion of her has improved, according to a new Gallup poll. In early January, the percentage of people who viewed Trump favorably and unfavorably was tied at 37 percent; as of early December, a 54 percent majority of Americans view her favorably while 33 percent view her unfavorably and 13 percent have no opinion. President Trump's approval rating has notched up 1 point in that same time period, to 41 percent now, but so has his unfavorable number, 56 percent.

The fact that more people like Melania Trump than President Trump "is consistent with Gallup's findings that recent first ladies are, on average, more popular than their husbands," Gallup says, though "Hillary Clinton averaged 1 point lower favorability than Bill Clinton over the course of his presidency." Still, like her husband, Melania Trump's popularity lags behind her predecessors at this point in her first year as first lady — Michelle Obama had a 61 percent favorable rating, Laura Bush's was 77 percent, and Hillary Clinton's was 58 percent.

Fewer women than men view Melania Trump favorably, 51 percent versus 57 percent, and the same is true of President Trump, with 33 percent of women and 50 percent of men viewing him favorably. Gallup conducted its poll Dec. 4-11 among 1,049 U.S. adults; it has a margin of sampling error of ±4 percentage points. Peter Weber